The present inventions relate generally to mechanisms sealing and protecting photonic devices in optoelectronic packages. More particularly, the photonic device is overmolded with a clear molding material. When appropriate, the clear molding material may be used to control the standoff distance between an optical fiber and the photonic device.
Optical networks have a wide variety of applications and are, for example, widely used within the telecommunications, data transmission and high speed networking industries. The optical devices used to convert electrical signals into light signals and light signals into electrical signals are key components in any such optical network. Generally, such devices include one or more photonic elements (e.g. detectors and/or laser emitters) together with the electronic circuitry necessary to drive the photonic elements (e.g., receiver, transmitter or transceiver circuitry). Although a wide variety of optical transceiver devices are currently commercially available, there are always continuing efforts to improve their design and functionality as well as to lower their production costs.
At the time of this writing, most commercially available photonic devices are placed in sealed packages such as TO (transistor outline) metal cans or ceramic chip carriers. A transparent glass or plastic window is then positioned over the active area of the photonic device. The die is typically adhered to the carrier and electrically connected to traces on the carrier using wire bonding.
One issue that is fundamental to the design of any photonic device is the desire to (relatively) efficiently optically couple each active facet (i.e., emitter or receiver) to its associated optical fiber. When photonic devices are packaged in metal cans or ceramic carriers, there is an inherent standoff distance between the optical fiber or fiber bundle and the active facets of the devices. Typical standoff distances in currently available packages tend to be in the range of 1–5 mm depending upon the type of packaged used. At these distances, it becomes important to collimate the optical fibers to insure good optical coupling between the fibers and the photonic elements. Typically, collimation is accomplished by providing a simple lens at the termination of the optical fiber.
Although the described packaging techniques work well, they are relatively expensive to produce. Accordingly, there are continuing efforts to provide improved optical component packaging techniques that help reduce the size and costs of the optical components.